Can I model a house in a way that I can turn details on and off?
There are several ways to go about this. You named most of them in your question actually.. You could use parenting, and you could even use multiple files, however here are the most practical ones I could think of: 


Hide and show objects as needed
You can hide the selected objects with H, and you can unhide all objects with AltH. You can also use the outliner to toggle visibility, which combined  with the Groups view, you could use to hide/unhide groups of objects (you can group the selected objects with CtrlG).
Use multiple scenes
For an object you want to appear in more than one scene, select it and press CtrlL> Objects to scene, then select the scene you want it to appear in (aside from the current scene).
Note that modifying the object in any scene will update it in the other scenes as well.
Use layers
You can move the selected object(s) to different layers by pressing M and selecting the layer(s) you want the object to appear on (use Shift to select multiple layers).
Any objects on at least one of the visible layers will be displayed (unless hidden in some other way).

Some useful shotcuts for handling layers:


Pressing numbers 1..9 (0 is layer 10) will set that layer as the visible layer. You can use Shift to keep the existing visible layers visible, and you can use Alt to operate on layers 11..20.
` will toggle all layers visible (press it again to go back to the previous layers)


This is probably the most intuitive option (also arguably the fastest, as you can use convenient shortcuts like M), however you are limited to 20 layers and layers cannot be named (I sometimes write down what is in each layer with the text editor).




I assumed this is just for real-time display. If you want to animate and render this, then that's something else..